Touch Panel Display System with Illumination and Detection Provided from a Single Edge

ABSTRACT

A touch panel that has a front surface, a rear surface, a plurality of edges and an interior volume. An energy source is positioned in proximity to a first edge of the touch panel and is configured to emit energy that is propagated within the interior volume of the touch panel. A diffusing reflector is positioned in proximity to the front surface of the touch panel for diffusively reflecting at least a portion of the energy that escapes from the interior volume. At least one detector is positioned in proximity to the first edge of the touch panel and is configured to detect intensity levels of the energy that is diffusively reflected across the front surface of the touch panel. Preferably, two detectors are spaced apart from each other in proximity to the first edge of the touch panel, to allow calculation of touch locations using simple triangulation techniques.

TECHNICAL FIELD

The present invention relates generally to a touch panel display systemthat allows a user to interact with displayed information by touching onor near a surface of the system. More particularly, the presentinvention relates to a touch panel display system that includes anenergy source and a detector positioned on a single side of the touchpanel, whereby a surface of the touch panel is illuminated by the energysource and an interruption of the illumination by a touch on or near thesurface of the touch panel is detected by the detector.

BACKGROUND OF INVENTION

Touch panel display systems (also commonly known, for example, as touchscreens systems) can allow a user to touch on or near an area of a touchpanel (also commonly referred to as a touch screen) to enter a commandto a computer system and, thereby, control the operation of the computersystem. Touch panel display systems can provide an intuitive method bywhich people can easily interact with and control various functionsperformed by a computer system. For example, a touch panel displaysystem can display icon elements representing a keyboard to allow a userto input text to a computer system. Such interactive graphicalrepresentations of a keyboard or other information can eliminate theneed to configure a computer system with certain other input devices,such as a keyboard or mouse.

Touch panels can be produced in a variety of types and sizes and can beused as part of a wide variety of systems, such as kiosks, personalcomputer systems, portable consumer electronics (e.g., cellulartelephones, personal digital assistants, hand held computers, video gamedevices, etc.), domestic appliances, vehicles information systems (e.g.,GPS locators), and industrial equipment and tools. Businesses can usetouch panel display systems to display information to potentialcustomers and to receive feedback or commands from customers regardinginformation they desire. Touch panel display systems can also be used tofacilitate business and/or consumer transactions, such as banking or thesale of merchandise or services. Earlier prior art approaches to touchpanel display systems typically operated based on principles such ascapacitance, resistance, or acoustic waves. More recent prior artapproaches to touch panel display systems operate based on detection ofemitted energy (e.g., infrared energy) and image processing, which canoften be more accurate and reliable than the earlier prior artapproaches.

One recent approach to touch panel display systems involves thedetection of light emitted across a touch panel surface from anoscillating or rotating emission system, such as a fixed emitter and anoscillating or rotating reflector. A similar approach involves thedetection of light emitted across a touch panel surface by anoscillating or rotating detector assembly. In either of theseapproaches, a user's touch is detected based on the interruption of thelight emitted across the touch panel surface. However, these approachesrely on moving components, which are susceptible to mechanical failure,can decrease the detection accuracy of a user's touch, and lead toincreased production costs and times.

Another recent approach to touch panel display systems involves the useof video cameras positioned behind the touch panel to detect lightinternally reflected within the touch panel. A touch, resulting from auser placing a finger or rubbery object directly on the touch panelsurface, interrupts the internal reflection of light in the touch paneland causes a bright or dark image to appear on the touch panel, which isdetected by the video camera. A user's touch of the touch panel willtypically not be detected by this approach if it is made with less thanfirm contact by a finger or by an object of less than sufficientdensity. Furthermore, this approach involves video imaging, whichusually requires expensive imaging components and complicated processingoperations to detect the location of a touch on the touch panel.Additionally, the need to position the video camera behind the touchpanel can make the display system bulky and limit its application.

Yet another recent approach to touch panel display systems involves theuse of video cameras to acquire real-time images of the user touching onor near the touch panel surface. Such images are then processed todetermine the location of the user's touch in relation to the touchpanel. Touch panel display systems based on this approach usually alsorequire expensive video imaging components and complicated processingoperations to detect a touch location. Furthermore, the accuracy ofthese video-based systems can be sensitive to variations in thesurrounding light levels (e.g., ambient light levels), which can furthercomplicate the processing required to detect a touch. Moreover, thisapproach typically requires video cameras to be positioned on multiplesides of a touch panel display system in order to provide accurate touchdetection, which usually also increases the production cost.

Accordingly, there remains a need in the art for a touch panel displaysystem that can accurately detect a user's touch on or near a touchpanel surface, but is less expensive and time consuming to produce ascompared to existing approaches. There is also a need in the art for atouch panel display system that can be implemented with less expensivecomponents and less complicated processing operations to detect touchlocation. There furthermore is a need in the art for a touch paneldisplay system that can detect a touch without the need to positionenergy emission and/or detection components on multiple sides of a touchpanel, thereby reducing the size of the system. Moreover, there is aneed in the art for a touch panel display systems that has reducedsensitivity to variations in surrounding light levels, thereby furthersimplifying the processing operations to detect a touch.

SUMMARY OF INVENTION

The present invention, in accordance with exemplary embodimentsdescribed herein, provides a touch panel display system withillumination and detection functionality provided from a single edge ofthe touch panel. This touch panel display system can accurately detect auser's touch (e.g., with a finger, stylus, or other object) on or nearthe touch panel, but is less expensive and less time consuming toproduce as compared to existing designs. The touch panel display systemcan also be implemented with less expensive components and can usesimple processing operations to determine a touch location. Furthermore,the touch panel display system is not particularly sensitive tovariations in surrounding light levels and other ambient conditions,which can also simplify the processing operations to detect a touch.

In accordance with certain aspects of the present invention, the touchpanel display system includes a touch panel that is positioned in frontof a display screen so that objects on the display screen can be seenthrough the touch panel. Alternatively, the touch screen may double as adisplay screen. The touch panel has a front surface, a rear surface, aplurality of edges and an interior volume. The touch panel may beconstructed from any suitable transparent material, such as glass,plastic and/or thermoplastic.

The touch panel display system also includes an energy source positionedin proximity to a first edge of the touch panel and configured to emitenergy that is propagated within the interior volume of the touch panel.One or more reflectors may be positioned and configured to guide theenergy emitted by the energy source into the interior volume of thetouch panel. The energy emitted by the energy source may be non-visiblelight energy, visible light energy, microwave energy, acoustic energy,etc. The energy source may include a plurality of energy emitters, suchas light emitting diodes or the like, positioned at spaced intervals inproximity to the first edge of the touch panel. A reflective componentmay optionally be applied to at least one edge of the touch panel forcontrolling the direction of the energy propagated within the interiorvolume of the touch panel.

At least a portion of the energy propagated through the interior volumeof the touch panel will necessarily escape toward the front surface ofthe touch panel. One or more reflectors may also be configured andpositioned to guide the energy outward from within the interior volumeof the touch panel toward the front surface of the touch panel. Adiffusing reflector is positioned in proximity to the front surface ofthe touch panel for diffusively reflecting across the front surface atleast a portion of the energy that escapes from the interior volume ofthe touch panel. A touch on or near the front surface of the touch panelresults in a variation in the intensity levels of the energy that isdiffusively reflected across the front surface.

At least one detector is positioned in proximity to the first edge ofthe touch panel and is configured to detect intensity levels of theenergy that is diffusively reflected across the front surface of thetouch panel. Preferably, two detectors are included and are spaced apartfrom each other in proximity to the first edge of the touch panel. Theuse of two or more detectors allows touch locations to be determinedthrough simple triangulation calculations. The detectors may be, forexample, optical imaging devices of sufficient sensitivity to detectvariations in the intensity levels of the energy that is diffusivelyreflected across the front surface of the touch panel. One or morereflector may be positioned and configured to guide the energy reflectedacross the front surface of the touch panel toward the detectors.

These and other aspects of the invention will be described further inthe detailed description below in connection with the appended drawingsand claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplary perspective view of a touch panel display systemin accordance with exemplary embodiments of the present invention.

FIG. 2 is an exemplary partial perspective view of a touch panel displaysystem in accordance with exemplary embodiments of the presentinvention.

FIG. 3A is a cross-sectional side view of the exemplary touch paneldisplay system illustrated in FIG. 1.

FIG. 3B is a cross-sectional side view of the exemplary touch paneldisplay system illustrated in FIG. 2.

FIG. 4 is a block diagram illustrating an exemplary touch panel displaysystem interfaced with an exemplary computing device in accordance withexemplary embodiments of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION

Exemplary embodiments of the present invention will hereinafter bedescribed with reference to the drawings, in which like referencenumerals represent like elements throughout the several figures. FIG. 1is an exemplary perspective view of a touch panel display system 100 inaccordance with an exemplary embodiment of the present invention. Asused herein, the term “touch panel display system” is meant to refer toa touch panel 110 and the hardware and/or software components thatprovide touch detection functionality. A touch panel display system 100is also commonly referred to as a touch screen system.

The exemplary touch panel display system 100 is shown adjacent to anexemplary display device (i.e., video monitor) 190. The display device190 may be interfaced to a personal computer (not shown), which mayexecute software for detecting touches on or near the touch panel 110.The illustration in FIG. 1 of the touch panel display system 100adjacent to the display device 190 represents an exemplary applicationof the touch panel display system 100. For example, the touch paneldisplay system 100 may be positioned and/or secured in front of thedisplay device 190, so that a user can view and interact with the visualoutput (e.g., 196, 197, 198) of the display device 190 through the touchpanel 110.

Thus, the touch panel display system 100 may have over-lay or retrofitapplications for existing display devices 190. However, it should beunderstood that other applications of the exemplary touch panel displaysystem 100 are contemplated by the present invention. For example, thetouch panel display system 100 may be applied as an integrated componentof a display device 190 and may, in that regard, also function as adisplay screen for the display device 190. The exemplary touch paneldisplay system 100 may be used in conjunction with display screens 190of all sizes and dimensions, including but not limited to the displayscreens of small handheld devices, such as mobile phones, personaldigital assistants (PDA), pagers, etc.

The touch panel 110 may also be referred to as a “touch screen” or a“touch display.” At least a portion of the touch panel 110 is typicallytransparent and/or translucent, so that images (e.g., 196, 197, 198) orother objects can be viewed through the touch panel 110 and light and/orother forms of energy can be transmitted within or through the touchpanel 110 (e.g., by reflection or refraction). For example, the touchpanel 110 may be constructed of a plastic or thermoplastic material(e.g., acrylic, Plexiglass, polycarbonate, etc) and/or a glass type ofmaterial. In certain embodiments, the touch panel may be polycarbonateor a glass material bonded to an acrylic material. The touch panel 110may also be constructed of other materials, as will be apparent to thoseskilled in the art. The touch panel 110 may also be configured with adurable (e.g., scratch and/or shatter resistant) coating.

The touch panel 110 has a front surface 111 and a rear surface 109, eachdefined by the height and width of the touch panel 110. The frontsurface 111 may also be referred to herein as the “touch surface.” Thetouch panel 110 also has a depth, which defines a top edge 112, bottomedge 115, right side edge 116, left side edge 117, and interior volumeof the touch panel 110. The interior volume of the touch panel 110 maycomprise a solid volume of material(s), material(s) of varied density,or a void (possibly filled with liquid, gas plasma, etc). It is notedthat although the exemplary touch panel 110 is described as having arectangular shape, various other configurations are possible and will beapparent to those skilled in the art. The touch panel 110 may or may notinclude a frame, i.e., a casing or housing that surrounds the perimeterof the touch panel 110. In the exemplary embodiment shown in FIG. 1, thetouch panel 110 does not include a frame.

The touch panel display system 100 includes an energy source 120 that isconfigured to emit energy, for example, in the form of pulses, waves,beams, etc. (generally referred to herein as “energy beams” forsimplicity). The energy source 120 is typically positioned within oradjacent (e.g., in proximity) to a single edge of the touch panel 110.For example, as illustrated in FIG. 1, the energy source 120 may bepositioned within or along the bottom edge 115 of the touch panel 110.However, it should be understood that the energy source 120 (as well asother components discussed herein, such as the detectors 130, 131) canbe positioned within or along any other single, edge of the touch panel110 (e.g., the top edge 112, right edge 116, or left edge 117) inaccordance with other embodiments of the invention.

The energy source 120 may emit one or more of various types of energy.For example, the energy source 120 may emit infrared (IR) energy.Alternately, the energy source 120 may emit visible and/or non-visiblelight energy (e.g., at one or more frequencies or spectrums), microwaveenergy, acoustic energy, or other types of energy that will be apparentto those skilled in the art. The energy source 120 may include one ormore separate emission sources (emitters, generators, etc.) For example,the energy source 120 may include one or more infrared light emittingdiodes (LEDs). As another example, the energy source 120 may include oneor more microwave energy transmitters or one or more acoustic wavegenerators.

As is further illustrated in FIG. 1, the energy source 120 is positionedand configured such that it emits energy beams 140 into the interiorvolume of the touch panel 110. Reflectors or prisms may be used, as orif required, in order to guide the emitted energy beams 140 into theinterior volume of the touch panel 110. As known in the art, if theenergy beams 140 are emitted into the interior volume of the touch panel110 at angles of incidence greater than a critical angle, they will betotally reflected within the interior volume of the touch panel 110.Those skilled in the art will appreciate that energy beams 140 may alsobe directly propagated through and/or refracted within the interiorvolume of the touch panel 110. Therefore, references herein to the“internal reflection” of energy beams 140 are used for convenience andare not intended to limit the scope of the present invention.

A reflective component 113 may be added to one or more edge (112, 115,116, 117) of the touch panel 110, so as to aide or enhance the internalreflection of energy beams 140 and thereby control the direction of theenergy beams 140. The one or more reflective component 113 may be anintegral part of the touch panel 110. For example, a reflectivecomponent 113 may be created by varying the density, polarization,translucence or some other property of an edge (112, 115, 116, 117) ofthe touch panel 110. Alternatively, a reflective component 113 may be aseparate material, such as reflective tape, paint, metal, plastic, etc.,attached or mounted to an edge (112, 115, 116, 117) of the touch panel110.

The configuration of and choice of material for a reflective component113 may depend on the type of energy beams 140 employed in the touchpanel display system 100. For example, if the energy beams 140 used inthe touch panel display system 100 are visible or non-visible lightenergy (e.g., infrared energy), the reflective component 113 may have ametallic or mirror-like coating capable of reflecting such energy. Othertypes of materials may be used for reflecting other types of energy, aswill be apparent to those skilled in the art. It should be understoodthat the use of a reflective component 113 is entirely optional incertain embodiments.

Some portion of the energy beams 140 that are internally reflectedwithin the interior volume of the touch panel 110 will eventually escapevia the front surface 111, the rear surface 109 and any edge 112, 115,116, 117 of the touch panel 110 that is not covered by a reflectivecomponent 113. The energy beams 140 may be reflected out of the touchpanel 110 as a result of refraction (e.g., when their angle of incidenceis less than a critical angle) and optical coupling. The energy beams140 may also be directed out of the interior of the touch panel 110 byvariations in the reflective component 113. Energy beams 140 that escapevia the front surface 111 and/or any edge (designated as energy beams150 in FIG. 1) may be reflected across the front surface 111 of thetouch panel 110 by one or more diffusing reflector 114. Diffusingreflectors may be positioned on or adjacent (e.g., in proximity) to oneor more edges 112, 115, 116, 117 of the touch panel 110. For example, inthe case of the rectangular touch panel 110 illustrated in FIG. 1, adiffusing reflector 114 extends forward from the top edge 112, the rightedge 116 and the left edge 117 of the touch panel 110 forward of thefront surface 111.

The diffusing reflector 114 may be an integral part of the touch panel110 or may comprise separate material(s) mounted or connected (e.g.,bonded or otherwise attached) to the perimeter of the front surface 111and/or one or more of the edges 112, 116, 117 of the touch panel 110. Aswill be discussed further below, the diffusing reflector 114 typical hasa reflective quality that causes energy beams 150 to reflect off of itin various directions, for example, along the front surface 111 of thetouch panel 110. The reflective quality of the diffusing reflector 114can be obtained, for example, by covering and/or coating one or moresurfaces of the diffusing reflector 114 with a white colored paint orother substance that can provide the desired reflective property.Furthermore, one or more surfaces of the diffusing reflector 114 mayhave different textures, shapes, etc. (e.g., smooth, rough, uniform,non-uniform, etc.) to provide the desired reflective quality of thediffusing reflector 114.

In some embodiments, the diffusing reflector 114 may possess itsreflective property as a result of the material(s) of which it isconstructed. Additionally, the diffusing reflector may be formed as asingle and/or continuous component or it may be formed of severalindependent components. Other configurations of the diffusing reflector114 are also possible and are deemed to be within the scope of thepresent invention. The diffusive reflector 114 can be angled or shapedalong its edges so as to control the direction of reflection, therebyensuring that more of the energy beams 150 are directed across the frontsurface 111 of the touch panel 110.

In a preferred embodiment, a diffusing reflector 114 is constructed froma translucent or transparent bezel. The bezel 114 may be constructedfrom the same or a similar material as the touch panel 110. An edge ofthe bezel 114 is covered or coated with the above-described reflectivecomponent 113. As mentioned above, the reflective component 113 maysimply be a coat of white paint. The reflective component 113 providesthe desired diffusively reflective properties to the bezel 114. Thispreferred embodiment is therefore characterized by a simple and costeffective construction.

It should be appreciated that the ray or arrow-like representations ofenergy beams 140, 150 within the several figures hereof are intended torepresent exemplary transmission or propagation paths of wave fronts orpulse fronts, since most types of energy are typically propagated assome form of oscillating (e.g., sinusoidal) wave or periodic pulse.Moreover, it should be understood that the illustrated representationsof energy beams 140, 150 are not intended to be limiting regarding thedetails of the transmission, reflection, refraction, etc.

Energy beams 150 that are reflected across the front surface 111 of thetouch panel 110 are detected by detectors 130, 131. These detectors 130,131 may be configured to monitor and/or detect variations (changes,etc.) in the energy beams 150. For example, a touch 170 (e.g., by afinger, stylus, or other object) on or near the front surface 111 of thetouch panel may cause a level of interruption of the reflected energybeams 150 such that the touch location 170 appears as a shadow orsilhouette when detected by the detectors 130, 131. In some embodiments,filtering may be employed by the detectors 130, 131 and/or software inorder to enhance the detection of energy beam intensity variations.However, the contrast of intensities between the energy beams 150 andsurrounding noise may be sufficient to negate the need for filtering.

The detectors 130, 131 are positioned within or adjacent (e.g., inproximity) to the touch panel 110 such that they can monitor and ordetect the energy beams 150 that are reflected across the front surface111. Reflectors and/or prisms can be used, as or if needed, depending onthe location of the detectors 130, 131, to allow the detectors 130, 131to detect the energy beams 150. In the example shown in FIG. 1, thedetectors 130, 131 are positioned within or along the bottom edge 115 ofthe touch panel 110, one in each corner. At least two spaced apartdetectors are included in preferred embodiments, so that the location ofthe touch can be determined using triangulation techniques, as describedbelow.

A detector 130, 131 can be any device that is capable of detecting(e.g., imaging, monitoring, etc.) variations in the energy beams 150reflected across the front surface 111 of the touch panel 110. Forexample, a suitable detector 130, 131 may be one of various types ofcameras, such as an area scan or line scan (e.g., digital) camera. Suchan area scan or line scan camera may be based on complementary metaloxide semiconductor (CMOS) or charge coupled device (CCD) technologies,which are known in the art. Furthermore, monochrome (e.g., gray-scale)cameras may be sufficient because the detectors 130, 131 do not need toacquire detailed color images.

While cameras generally are more expensive than other types of detectordevices that can be used in touch panel display systems 100, such asphoto-detectors (e.g., photo-diodes or photo-transistors), they allowgreater accuracy for touch detection. As known in the art, area scan orline scan cameras (particularly those with monochrome capability) aretypically less expensive than cameras configured to acquire detailedimages and/or that have color detection capability. Thus, relativelycost effective area scan or line scan cameras can provide the touchpanel display system 100 with very accurate touch detection capability.However, it should be understood that other devices may be used toprovide the functions of the detectors 130, 131 in accordance with otherembodiments of the invention.

Accordingly, the touch panel display system 100 of the present inventionis configured to detect a touch 170 (e.g., by a finger, stylus, or otherobject) based on detected variations in energy beams that are reflectedacross the front surface 111 of the touch panel 110. The energy source120 emit energy beams 140 that are directed into and internallyreflected within the interior volume of the touch panel 110. Reflectivecomponent 113 may be used to minimize unintended losses while the energybeams 140 are channeled through the interior volume of the touch panel110. Energy beams 140 that do escape toward the front surface 111 arereflected across the front surface 111 by one or more diffusingreflector 114.

The reflected energy beams 150 diffuse across the front surface 111 andare monitored by the detectors 130, 131. The detectors 130, 131 may beconfigured to detect variation (e.g., a decrease, absence, etc.) in theintensity of the energy beams 150. As will be appreciated by those ofordinary skill in the art, the required output capacity of the energysource 120 to allow adequate detection by the detectors may be based onvarious factors, such as the size of the touch panel 110, the expectedlosses within the touch panel display system 100 (e.g., 1/distance²losses) and due to and the surrounding medium (e.g., air), speed orexposure time characteristics of the detectors 110, ambient lightcharacteristics, etc. As will be discussed with respect to subsequentfigures, the detectors 130, 131 transmit data regarding the energy beams150 (or variation therein) to a computing device (not depicted) thatexecutes software for processing said data and calculating the locationof the touch 170 relative to the touch panel 110.

FIG. 2 is an partial perspective view of an exemplary touch paneldisplay system 200, in accordance with certain other embodiments of thepresent invention. As indicated by the like reference numerals in FIG.2, the illustrate touch panel display system 200 includes many of thesame or substantially similar components as the previously describedtouch panel display system 100 of FIG. 1. In that regard, the touchpanel display system 200 includes an energy source 120 and energydetectors 130, 131 (not shown) positioned along the same edge (e.g., thebottom edge 115) of the touch panel 110. As described previously, thetouch panel 110 includes a front surface 111, a rear surface 109, a topedge 112, a bottom edge 115, a right edge 116 and a left edge 117. Thetouch panel 110 also includes an interior volume. Optionally, one ormore edge 112, 115, 116, 117 of the touch panel 110 may be covered by areflective component 113 (not depicted) to facilitate the internalreflection of energy beams 140 within the interior volume of the touchpanel 110. The touch panel 110 includes one or more diffusing reflector114 for reflecting energy beams 150 across the front surface 111 of thetouch panel 110.

As a variation of the previously described touch panel display system100 of FIG. 1, the energy source 120 and the detectors 130, 131 includedin the touch panel display system 200 of FIG. 2 are positioned adjacentto and rearward of the rear surface 109 of the touch panel 110. Forexample, the energy source 120 and the detectors 130, 131 may be mountedon or within a rear support member 208. The rear support member 208 maybe formed as an integral part of the touch panel 110, or may beconstructed separately from the touch panel 110 and attached or mountedthereto. For example, the support member 208 may be a circuit board orother mounting surface that can support the energy source 120 and thedetectors 130, 131 in appropriate positions for the operation of thetouch panel display system 200. The positioning of the energy source 120and the detectors 130, 131 on or within the support member 208 can, forexample, provide additional protection to these components and may alsofacilitate a compact and efficient profile for the touch panel displaysystem 200.

The exemplary touch panel display system 200 of FIG. 2 includes one ormore reflectors 217, 218, 219, positioned within or adjacent to thetouch panel 110. For example, the touch panel display system 200includes a first reflector 217 positioned within or adjacent to thebottom edge 115 of the touch panel 110 for guiding energy beams 140 fromthe energy source 120 into the touch panel 110. The first reflector 217can be shaped and/or positioned such that it causes at least a portionof the energy beams 140 to be internally reflected within the interiorvolume of the touch panel 110. Similarly, a second reflector 218 ispositioned within or adjacent to the top edge 112 of the touch panel110. The second reflector 218 can be shaped and/or positioned such thatcauses at least a portion of the energy beams 140 to be directed out ofthe interior volume of the touch panel 110 toward the front surface 111and the diffusing reflector(s) 114.

A third reflector 219 and corresponding fourth reflector (not shown) canalso be positioned within or adjacent to the bottom edge 115 of thetouch panel 110. The third reflector 219 and fourth reflector can beshaped and/or positioned so as to guide energy beams 150 from the frontsurface 111 of the touch panel 110 toward the detectors 130, 131. Incertain embodiments, the third reflector 219 and fourth reflector arepositioned along or within the bottom edge 115 of the touch panel, oneat each corner. Other configurations and locations for the thirdreflector 119 and the fourth reflector are possible. In addition, thefunction of the third reflector 219 and fourth reflector may beperformed using only the third reflector 119, or using multiplereflectors.

The above described reflectors 217, 218, 219 can be constructed from anymaterial and in any configuration capable of reflecting energy beams140, 151. For example, if the energy source 120 emits visible ornon-visible light energy, one or more of the reflectors 217, 218, 219may be constructed of a metallic material in a specular configuration.As another example, one or more of the reflectors 217, 218, 219 may beconstructed of an acrylic and/or glass type of material (e.g., the samematerial as the touch panel 110), in a prismatic or partially prismaticconfiguration, to reflect visible or non-visible light energy. Thereflectors 217, 218, 219 may also be constructed of other materials andin other configurations (such as a mirror prism, an acoustic reflector,or a microwave reflector) in accordance with the type of energy thatthey are used to reflect.

The use of one or more of the reflectors 217, 218, 219 may be optionalin certain embodiments. For example, the touch panel display system 200might only include reflectors 217, 219 along the bottom edge 115 of thetouch panel 110 for guiding energy beams 140, 150 from the energy sourceand to the detector 130. The direction of energy beams 140 outward fromthe interior volume of the touch panel 110 to the front surface 111 maybe facilitated by a reflective component 113 as discussed above and/orby the geometry of the edges 112, 115, 116, 117, front surface 111and/or rear surface 109 of the touch panel 110. A more detaileddiscussion of the exemplary operation of the touch panel display system200 with respect to the reflectors 217, 218, 219 will be presentedbelow.

FIG. 3A is a cross-sectional side view of the exemplary touch paneldisplay system 100 illustrated in FIG. 1. As shown, the energy source120 and the detectors 130, 131 (not shown) may all be positioned alongor within the bottom edge 115 of the touch panel 110. In the illustratedembodiment, the energy source 120 is positioned behind the detectors130, 131, relative to the depth of the touch panel 110. The energysource 120 is shown as being positioned within the bottom edge 115 ofthe touch panel 110, and configured for emitting and reflecting energybeams 140 into the interior volume of the touch panel 110. The detectors130, 131 are shown as being positioned forward of the front surface 111of the touch panel 110, and configured for line-of-sight exposure to theenergy beams 150 reflected across the front surface 150. For example,the detectors 130, 131 may be mounted on or within a front supportmember 302, which may be attached to or formed as an integral part ofthe touch panel 110.

As discussed above, the interior volume of the touch panel 110 can actas a guide (e.g., a wave guide or pulse guide) for the energy beams 140emitted from the energy source 120. At least a portion of the energybeams 140 that propagate through the interior volume of the touch panel110 escape and/or are directed out of the interior volume toward thefront surface 111 of the touch panel 110. The energy beams 140 mayenter/exit the interior volume of the touch panel 110 based on theoptical principles of coupling, reflection, refraction, etc. Aspreviously mentioned, a reflective component 113 (shown only one topedge 112) may be added to one or more edge 112, 115, 116, 117 of thetouch panel 110 in order to facilitate the desired propagation of theenergy beams 140. The reflective component 113 may also be applied to anedge of a bezel 114 that extends forward from the front surface 111 ofthe touch panel in order to provide diffusive reflective properties.

Due to the chosen positioning of the energy source 120 in theillustrated embodiment, additional reflectors (e.g., reflector 217 FIG.2) are not required for guiding the energy beams 140 from the energysource 120 into the interior volume of the touch panel 110. Likewise,the combination of the reflective component 113 on at least the top edge112 and the diffusive reflector 114 (e.g., a transparent or translucentbezel covered or coated with the reflective component 113) eliminatesthe need for additional reflectors (e.g., reflector 218 FIG. 2) forguiding energy beams 140 outward from the interior volume toward thefront surface 111. Energy beams that escape the interior volume of thetouch panel 110 toward the front surface 111 are diffusively reflectedacross the front surface by the one or more diffusing reflectors 114. Atouch 170 on or near the front surface 111 of the touch panel 110 willresult in a variation of the intensity of such energy beams 150. Thevariation in intensity will be detected by the detectors 130, 131. Dueto the chosen positioning of the detectors 130, 131 in the illustratedembodiment, additional reflectors (e.g., reflector 219 of FIG. 2) arenot required for guiding energy beams 150 reflected across the frontsurface 111 of the touch panel 110 toward the detectors 130, 131.

FIG. 3B is cross-sectional side view of the exemplary touch paneldisplay system 200 illustrated in FIG. 2. The energy source 120 and thedetectors 130, 131 (not shown) are again all positioned along the bottomedge 115 of the touch panel 110. In this illustrates embodiment, theenergy source 120 and the detectors 130, 131 are positioned rearward ofthe rear surface 109 of the touch panel 110. For example, the energysource 120 and the detectors 130, 131 may be mounted on or within a rearsupport member 208, which may be attached to or formed as an integralpart of the touch panel 110.

A first reflector 217 is used to guide energy beams 140 emitted by theenergy source 120 into the interior volume of the touch panel 110.Similarly, a second reflector 218 may be used to guide energy beams 140from the interior volume of the touch panel 110 outward toward the frontsurface 111. A third reflector 219 and a corresponding fourth reflector(not shown) guide energy beams reflected across the front surface 111 ofthe touch panel 110 toward the detectors 130, 131. The third reflector219 and fourth reflector may, for example, be mounted on or within afront support member 208. Accordingly, the use of one or more reflectors217, 218, 219 provides flexibility in the choice of position for boththe energy source 120 and the detectors 130, 131. Although the energysource 120 and detectors 130, 131 are shown in this illustratedembodiment as being positioned rearward of the rear surface 109, theycould alternatively be similarly positioned forward of the front surface111.

FIG. 4 is a block diagram illustrating an exemplary touch panel displaysystem 400 (e.g., the touch panel display system 100 of FIG. 1 or thetouch panel display system 200 of FIG. 2) interfaced to an exemplarycomputing device 401 in accordance with certain exemplary embodiments ofthe present invention. The computing device 401 may be functionallycoupled to a touch panel display system 400, either by a hardwire orwireless connection. The exemplary computing device 401 may be any typeof processor-driven device 401, such as a personal computer, a laptopcomputer, a handheld computer, a personal digital assistant (PDA), adigital and/or cellular telephone, a pager, a video game device, etc.These and other types of processor-driven devices will be apparent tothose of skill in the art. As used in this discussion, the term“processor” can refer to any type of programmable logic device,including a microprocessor or any other type of similar device.

The computing device 401 may include, for example, a processor 402, asystem memory 404, and various system interface components 406. Theprocessor 402, system memory 404, and system interface components 406may be functionally connected via a system bus 408. The system interfacecomponents 406 may enable the processor 402 to communicate withperipheral devices. For example, a storage device interface 410 canprovide an interface between the processor 402 and a storage device 411(e.g., removable and/or non-removable), such as a disk drive. A networkinterface 412 may also be provided as an interface between the processor402 and a network communications device (not shown), so that thecomputing device 401 can be connected to a network.

A display screen interface 414 can provide an interface between theprocessor 402 and a display device 190 (see FIG. 1.) The touch panel 110of the touch panel display system 400 may be display device 190 may bepositioned in front of or otherwise attached or mounted to the displaydevice 190. Alternately, the touch panel display system 400 may be anintegral part of a display device 190, wherein the touch panel 110 alsofunctions as the display screen 192 of the display device 190. One ormore input/output (“I/O”) port interfaces 416 may be provided as aninterface between the processor 402 and various input and/or outputdevices. For example, the detectors 130, 131 or other suitablecomponents of the touch panel display system 400 may be connected to thecomputing device 401 via an input port and may provide input signals tothe processor 402 via an input port interface 416. Similarly, the energysource 120 of the touch panel display system 400 may be connected to thecomputing device 401 by way of an output port and may receive outputsignals from the processor 402 via an output port interface 416.

A number of program modules may be stored in the system memory 404and/or any other computer-readable media associated with the storagedevice 411 (e.g., a hard disk drive). The program modules may include anoperating system 417. The program modules may also include aninformation display program module 419 comprising computer-executableinstructions for displaying images (e.g., 196, 197, 198 of FIG. 1) orother information on a display screen 192. Other aspects of theexemplary embodiments of the invention may be embodied in a touch panelcontrol program module 421 for controlling the energy source 120 and/ordetectors 130, 131 of the touch panel display system 400 and/or forcalculating touch locations relative to the touch panel 110 based onsignals received from the detectors 130, 131. The processor 402, whichmay be controlled by the operating system 417, can be configured toexecute the computer-executable instructions of the various programmodules. Furthermore, the images or other information displayed by theinformation display program module 419 may be stored in one or moreinformation data files 423, which may be stored on any computer readablemedium associated with the computing device 401.

As discussed above, when a user touches on or near the touch panel 110,a variation will occur in the intensity of the energy beams 150reflected across the front surface 111 of the touch panel 110. Thedetectors 130, 131 are configured to detect the intensity of the energybeams 150 reflected across the front surface 111 of the touch panel 110and should be sensitive enough to detect variations in such intensity.Information signals produced by the detectors 130, 131 and/or othercomponents of the touch panel display system 400 may be used by thecomputing device 401 to determine the location of the touch 170 relativeto the touch panel 110 (and therefore relative to the display screen192). The computing device 401 may also determine the appropriateresponse to a touch 170 on or near the touch panel 110

In accordance with some embodiments of the invention, data from thetouch panel display system 100 may be periodically processed by thecomputing device 401 to monitor the typical intensity level of theenergy beams 150 reflected across the front surface 111 of the touchpanel 110 when no touch 170 is present. This allows the system toaccount for, and thereby reduce the effects of, changes in ambient lightlevels and other ambient conditions. The computing device 401 mayoptionally increase or decrease the intensity of the energy beams 140emitted by the energy source 120, as needed. Subsequently, if avariation in the intensity of the reflected energy beams 150 is detectedby the detectors 130, 131, the computing device 401 can process thisinformation to determine that a touch 170 has occurred on or near thetouch panel 110.

The location of a touch relative to the touch panel 110 may bedetermined, for example, by processing information received from eachdetector 130, 131 and performing one or more triangulation calculations.By way of illustration, the computing device 401 may receive informationfrom each detector 130, 131 that can be used to identify the position ofan area of decreased energy beam intensity relative to each detector130, 131. The location of the area of decreased energy beam intensityrelative to each detector may be determined in relation to one or morepixels, or virtual pixels, of the touch panel 110. The location of thearea of decreased energy beam intensity relative to each detector maythen be triangulated, based on the geometry between the detectors 130,131, to determine the actual location of the touch relative to the touchpanel 110. Calculations to determine a touch location 170 can includealgorithms to compensation for discrepancies (e.g., lens distortions,ambient conditions, damage to or impediments on the touch panel 110,etc.), as applicable.

It should be appreciated by those skilled in the art that the foregoingdescriptions of the information display program module 419 and the touchpanel control program module 421 are exemplary. Certain functionality ofthe exemplary embodiments of the invention may be provided by way of anytype and number of program modules, created in any programming language,which may or may not be stored locally at the computing device 401. Forexample, the computing device 401 may comprise a network server, client,or appliance that may be configured to execute program modules (e.g.,419 and 421) that are stored on another network device and/or forcontrolling a remotely located touch panel display system 400.Accordingly, exemplary embodiments of the touch panel display system 400may provide an intuitive control interface for any computing device 401that is capable of determining the position of a touch 170 on or near atouch panel screen 110 based on data from, for example, the detectors130, 131.

Based on the foregoing, it can be seen that the present inventionprovides an improved touch panel display system. Many othermodifications, features and embodiments of the present invention willbecome evident to those of skill in the art. It should be appreciated,therefore, that many aspects of the present invention were describedabove by way of example only and are not intended as required oressential elements of the invention unless explicitly stated otherwise.Accordingly, it should be understood that the foregoing relates only tocertain embodiments of the invention and that numerous changes may bemade therein without departing from the spirit and scope of theinvention as defined by the following claims. It should also beunderstood that the invention is not restricted to the illustratedembodiments and that various modifications can be made within the scopeof the following claims.

1-39. (canceled)
 40. A touch panel display system, comprising: a touchpanel having a front surface, a rear surface, and a first edge and asecond edge disposed on opposite sides of the touch panel; an energysource positioned along the first edge of the touch panel and configuredto emit energy that is propagated within an interior volume of a waveguide, the wave guide having a quality that causes at least a portion ofthe energy escaping from the interior volume of the wave guide to travelacross the front surface of the touch panel in various directions; andat least one detector positioned along the first edge of the touch paneland configured to detect intensity levels of at least a portion of theenergy traveling across the front surface of the touch panel.
 41. Thetouch panel display system of claim 40, wherein the touch panel ispositioned in front of a display screen so that objects on the displayscreen can be seen through the touch panel.
 42. The touch panel displaysystem of claim 40, wherein the energy is selected from the groupconsisting of: non-visible light energy, visible light energy, microwaveenergy, and acoustic energy.
 43. The touch panel display system of claim40, wherein the energy source comprises a plurality of energy emitterspositioned at spaced intervals along the first edge of the touch panel.44. The touch panel display system of claim 43, wherein the energyemitters are embedded at least partially within the first edge of thetouch panel.
 45. The touch panel display system of claim 40, wherein theat least one detector comprises a first detector and a second detectorspaced apart from each other along the first edge of the touch panel.46. The touch panel display system of claim 45, wherein the firstdetector and the second detector are optical imaging devices ofsufficient sensitivity to detect variations in the intensity levels ofthe energy traveling across the front surface of the touch panel. 47.The touch panel display system of claim 1, wherein a touch on or nearthe front surface of the touch panel results in a variation in theintensity levels of the energy traveling across the front surface. 48.The touch panel display system of claim 1, wherein the touch panelcomprises a transparent material selected from the group consisting of:glass, plastic and thermoplastic.
 49. A touch panel display system,comprising: a touch panel having at least a front surface, a rearsurface, and a first edge and a second edge disposed on opposite sidesof the touch panel; an energy source positioned dong the first edge ofthe touch panel and configured to emit energy that is propagated withinan interior volume of a wave guide, the wave guide having a quality thatcauses at least a portion of the energy escaping from the interiorvolume of the wave guide to travel across the front surface of the touchpanel in various directions; a first detector positioned along the firstedge of the touch panel and configured to detect at least a portion ofthe energy traveling across the front surface of the touch panel; and asecond detector positioned along the first edge of the touch pad, spacedapart from the first detector, and configured to detect at least aportion of the energy traveling across the front surface of the touchpanel.
 50. The touch panel display system of claim 49, wherein the touchpanel is positioned in front of a display screen so that objects on thedisplay screen can be seen through the touch panel.
 51. The touch paneldisplay system of claim 49, wherein the energy is selected from thegroup consisting of: non-visible light energy, visible light energy,microwave energy, and acoustic energy.
 52. The touch panel displaysystem of claim 49, wherein the energy source comprises a plurality ofenergy emitters positioned at spaced intervals along the first edge ofthe touch panel.
 53. The touch panel display system of claim 52, whereinthe energy emitters comprise infrared light emitting diodes.
 54. Thetouch panel display system of claim 49, wherein the first detector andthe second detector are optical imaging devices of sufficientsensitivity to detect variations in the intensity levels of the energytraveling across the front surface of the touch panel.
 55. The touchpanel display system of claim 49, wherein a touch on or near the frontsurface of the touch panel results in a variation in the intensitylevels of the energy traveling across the front surface.
 56. The touchpanel display system of claim 49, wherein the touch panel comprises atransparent material selected from the group consisting of: glass,plastic and thermoplastic.
 57. A touch panel display system, comprising:a touch panel having a front surface, a rear surface, and a first edgeand a second edge disposed on opposite sides of the touch panel; anenergy source positioned along the first edge of the touch panel andconfigured to emit energy that is propagated within an interior volumeof a wave guide, the wave guide configured to cause at least a portionof the energy that escapes from the interior volume of the touch paneldiffusively to travel across the front surface; and at least onedetector positioned along the first edge of the touch panel andconfigured to detect intensity levels of the energy traveling across thefront surface of the touch panel; wherein the at least one detectorcomprises a first detector and a second detector spaced apart from eachother along the first edge of the touch panel; and wherein the firstdetector and the second detector are optical imaging devices ofsufficient sensitivity to detect variations in the intensity levels ofthe energy traveling across the front surface of the touch panel.
 58. Atouch panel display system, comprising: a touch panel having a frontsurface, a rear surface, and a first edge and a second edge disposed onopposite sides of the touch panel; an energy source positioned along thefirst edge of the touch panel and configured to emit energy that ispropagated within an interior volume of a wave guide, the wave guideconfigured to cause at least a portion of the energy that escapes fromthe interior volume of the wave guide to travel across the frontsurface; and at least one detector positioned along the first edge ofthe touch panel and configured to detect intensity levels of the energytraveling across the front surface of the touch panel; wherein a touchon or near the front surface of the touch panel results in a variationin the intensity levels of the energy traveling across the frontsurface.
 59. A touch panel display system, comprising: a touch panelhaving at least a front surface, a rear surface, and a first edge and asecond edge disposed on opposite sides of the touch panel; an energysource positioned along the first edge of the touch panel and configuredto emit energy that is propagated within an interior volume of a waveguide, the wave guide configured to cause at least a portion of theenergy that escapes from within the interior volume of the wave guide totravel across the front surface; a first detector positioned along thefirst edge of the touch panel and configured to detect the energytraveling across the front surface of the touch panel; and a seconddetector positioned along the first edge of the touch pad, spaced apartfrom the first detector, and configured to detect the energy travelingacross the front surface of the touch panel; wherein a touch on or nearthe front surface of the touch panel results in a variation in theintensity levels of the energy traveling across the front surface.
 60. Atouch panel display system, comprising: a touch panel having a frontsurface, a rear surface, and a first edge and a second edge disposed onopposite sides of the touch panel; an energy source positioned along thefirst edge of the touch panel and configured to emit energy that ispropagated within an interior volume of a wave guide; and at least onedetector positioned along the first edge of the touch panel andconfigured to detect intensity levels of energy escaping from the waveguide across the front surface of the touch panel; wherein the at leastone detector comprises a first detector and a second detector spacedapart from each other along the first edge of the touch panel, the firstdetector and the second detector comprising optical imaging devices ofsufficient sensitivity to detect variations in the intensity levels ofthe energy escaping from the wave guide across the front surface of thetouch panel.
 61. A touch panel display system, comprising: a touch panelhaving a front surface, a rear surface, and a first edge and a secondedge disposed on opposite sides of the touch panel; an energy sourceconfigured to emit energy that is propagated within an interior volumeof a wave guide; and at least one detector configured to detectintensity levels of energy escaping from the waveguide; wherein a touchon or near the front surface of the touch panel results in a variationin the intensity levels of the energy detected by the at least onedetector.
 62. A touch panel display system, comprising: a touch panelhaving at least a front surface, a rear surface, and a first edge and asecond edge disposed on opposite sides of the touch panel; an energysource positioned along the first edge of the touch panel and configuredto emit energy that is propagated within an interior volume of a waveguide; a first detector positioned along the first edge of the touchpanel and configured to detect energy escaping from the waveguide acrossthe front surface of the touch panel; and a second detector positionedalong the first edge of the touch panel, spaced apart from the firstdetector, and configured to detect energy escaping from the waveguideacross the front surface of the touch panel; wherein a touch on or nearthe front surface of the touch panel results in a variation in theintensity levels of the energy escaping from the waveguide across thefront surface.